This section studied a heavy quark moving through an infinite volume of quark-gluon plasma with a fixed velocity \(v\)  at a finite temperature \(T\) . The heavy quark feels a drag force and consequently losses energy. In the dual theory, the dynamic of this quark can be described by an open string whose endpoint is attached to the UV boundary of AdS space and moves at the constant speed of \(v\)  with a string tail into the AdS bulk [1]}, [2]}.
